Plunger assembly

ABSTRACT

A plunger assembly includes an outer elongated housing having an open end, an electric match having an electrical initiator and an explosive material, disposed in the housing. A plunger is disposed in and is moveable in the housing. A coupling device is provided for connecting the outer housing open end to a selected plunger receiver which is adapted to actuate a selected event. Application of an electrical charge to the initiator activates the explosive material to produce gas in the outer housing, which drives the plunger through the outer housing and into impact with the plunger receiver to actuate the selected event. In a preferred embodiment, the plunger assembly is a firing pin assembly and the plunger receiver is an explosive primer assembly.

REFERENCE TO PENDING PRIOR PATENT APPLICATION

[0001] This patent application claims the benefit of pending prior U.S.Provisional Patent Application Serial No. 60/302,945, filed Jul. 3, 2001by Paul A. Chambers for Electrically Fired Firing Pin Device, whichpatent application is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] This invention relates generally to plunger assemblies in whichmovement of a plunger into contact with a receiver is operative toinitiate a selected event. In a preferred embodiment, the plunger is afiring pin and the selected event in detonation of an explosive primer.

BACKGROUND OF THE INVENTION

[0003] Initiation of an explosive, or an explosive train, usually isaccomplished by imposing on the explosive, or primer therefor, a highvoltage spark, or imposing on a primer a mechanical impact. In general,the high voltage spark system is used in multi-use devices and themechanical impact system is used in disposable one-use systems.

[0004] The spark system requires the availability of a high voltagesource, and impact systems are generally large and cumbersome, areadapted to provide an impact of a single preset force, and are notadapted to be fired remotely.

[0005] There is required a mechanical impact assembly which mayincorporate a selected impact force and which can be initiated by anelectrical charge of a selected voltage, to provide a suitable minimallyrequired electrical charge to activate an impact on a given explosiveprimer.

[0006] More generally, there is need for a plunger assembly wherein theplunger in propelled by a minimally required electrical charge toactivate a selected plunger receiver at a selected force to initiate adesired event. There is further required such an assembly as isrelatively small and easy to handle, and which may be fired from aremote location.

SUMMARY OF THE INVENTION

[0007] An object of the invention is, therefore, to provide a relativelysmall, easy to handle and remotely activatable electrically actuatedplunger assembly wherein a plunger is propelled at a selected force intoimpact with a plunger receiver for initiation of a desired event.

[0008] A further object of the invention is to provide such an assemblyas a firing pin assembly wherein a firing pin is propelled at a selectedforce into impact with an explosive primer to initiate detonation of theexplosive.

[0009] With the above and other objects in view a feature of theinvention is the provision of a plunger assembly comprising an outerelongated housing having an open end, and an electric match, comprisingan electrical initiator and an explosive material, disposed in thehousing. A plunger is disposed in the housing and is movable in thehousing. A coupling device is provided for connecting the outer housingopen end to a selected plunger receiver adapted to activate a selectedevent. Upon application of an electrical charge to the initiator, theinitiator actuates the explosive material to produce gas in the outerhousing, which drives the plunger out the open end of the outer housingand into impact with the plunger receiver to actuate the selected event.

[0010] In accordance with a further feature of the invention, there isprovided a firing pin assembly comprising an outer elongated housinghaving an open end, and an electric match, comprising an electricalinitiator and an explosive material, disposed in the housing. A firingpin is disposed in the housing and is moveable in the housing. Acoupling device is provided for connecting the outer housing open end toan explosive primer. Application of an electrical charge to theinitiator activates the explosive material to produce gas in the outerhousing, which drives the firing pin out of the open end of the outerhousing and into impact with the explosive primer.

[0011] The above and other features of the invention, including variousnovel details of construction and combinations of parts, will now bemore particularly described with reference to the accompanying drawingsand pointed out in the claims. It will be understood that the particulardevice embodying the invention is shown by way of illustration only andnot as a limitation of the invention. The principles and features ofthis invention may be employed in various and numerous embodimentswithout departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Reference is made to the accompanying drawings in which is shownan illustrative embodiment of the invention, from which its novelfeatures and advantage will be apparent, wherein corresponding referencecharacters indicate corresponding parts in the views of the drawings,and wherein:

[0013]FIG. 1 in a perspective exploded view of one form of plungerassembly illustrative of an embodiment of the invention, shown with anexemplary plunger receiver; and

[0014]FIG. 2 is a generally centerline sectional view of the assembly ofFIG. 1 in an assembled condition and joined to the illustrative plungerreceiver.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0015] Referring to FIG. 1, it will be seen that an illustrativeassembly 8 includes an outer tubular housing 10 having an open end 12.An electric match 14, comprising an electrical initiator and explosivematerial adjacent the electrical initiator, is disposed in the housing10. A plunger 16 is disposed in the housing 10 and is moveable axiallyin the housing. A coupling device 18 is mounted rotatably on the openend 12 of the housing 10, being fitted on a flared collar 20 around thehousing open end 12, as shown in FIG. 2.

[0016] The assembly 8 further includes structure, such as an innertubular housing 22, disposed in the outer tubular housing 10, forretaining the electric match 14 in an appropriate position in the outerhousing 10. The outer housing may be provided with crimped portions 24for bonding the inner tubular housing 22 in place. Alternatively, theinner and outer housings may be bonded together adhesively by a bondingagent.

[0017] The coupling device 18 may be a nut adapted for interlockingengagement with a selected plunger receiver 30, the nut 18 beingprovided with a central bore 26 therethrough, the bore threadedlyreceiving a portion of the plunger receiver 30, to connect the assemblyto the plunger receiver.

[0018] As shown in FIG. 2, the plunger 16 is disposed in the outerhousing 10 at an open end 29 of the inner housing 22 and spaced from theopen end 12 of the outer housing 10.

[0019] The assembly is provided with a plug 28 (FIG. 1) which, prior touse of the assembly, is engaged in the bore 26 of the coupling device 18to close the interior of the assembly. The plug 28 may be removed, as byunscrewing, from the coupling device 18, and the plunger receiver 30screwed into the coupling device in preparation for use of the assembly.

[0020] The electric match 14 is provided with a pair of electrical leads32 which extend through the inner tubular housing 22 and out a closedend 34 of the outer tubular housing 10, and are connectable to a powersource (not shown).

[0021] In a preferred embodiment of the invention, the assembly hereindescribed constitutes a firing pin assembly, the plunger 16 constitutesa firing pin, and the plunger receiver 30 constitutes an explosiveprimer assembly, including a primer 36 (FIG. 2).

[0022] In preparing for use of the assembly 8, the assembly is takenfrom a protective package (not shown) and the plug 28 is removed fromthe nut 18. The nut 18 is then attached to the primer assembly 30 andthe electrical leads 32 are attached to the power source.

[0023] Upon closure of a switch, as by pushing a button, squeezing atrigger, or as by a monitoring device, or time-activated device, or thelike (not shown), current is directed to the electric match initiatorwhich detonates the electric match explosive material to produce gaswhich drives the firing pin 16, which accelerates through the spacebetween the firing pin 16 and the primer 36, and into impact with theprimer 36 to detonate an explosive.

[0024] In the broader context of the invention, the gas drives theplunger 16 into impact with the plunger receiver 30 to actuate a desiredevent, such as sounding an alarm, flowing fire-quenching matter into anarea, shutting down a power generator, or the like.

[0025] There is thus provided a small, easily handled plunger assemblyactivated electrically either locally or remotely, manually orautomatically. Typically, the plunger assembly, less the outwardlyextending lead wires, is about four inches or so, in length. Theelectric match component, described hereinabove, is a well-knowncommercially available part, available in several explosive weights andpowers, and activatable by different voltages. Thus, for a particularapplication, a user can select an electric match activated by a very lowvoltage, as by a small battery, or by higher voltage, and having arelatively low explosive power. Conversely, the match can exhibit a highexplosive power, initiated by a pulse of a suitable selected voltage.

[0026] It will be understood that many additional changes in thedetails, materials, steps and arrangements of parts, which have beenherein described and illustrated in order to explain the nature of theinvention, may be made by those skilled in the art within the principlesand scope of the invention as expressed in the appended claims.

What is claimed is:
 1. A plunger assembly comprising: an outer elongatedhousing having an open end; an electric match, comprising an electricalinitiator and an explosive material, disposed in said housing; a plungerdisposed in said housing and moveable in said housing; and a couplingdevice for connecting said outer housing open end to a selected plungerreceiver adapted to actuate a selected event; wherein application of anelectrical charge to said electric match initiator activates saidelectric match explosive material to produce gas in said outer housingwhich drives said plunger through said outer housing and into impactwith the plunger receiver to activate the selected event.
 2. Theassembly in accordance with claim 1 and further comprising structuredisposed in said outer housing for retaining said electric match.
 3. Theassembly in accordance with claim 2 wherein said retaining structurecomprises an inner housing.
 4. The assembly in accordance with claim 3and further comprising means for retaining said inner housing in placein said outer housing.
 5. The assembly in accordance with claim 4wherein said housings are tubular members and said outer housing isbonded to said inner housing to effect the retaining of said innerhousing.
 6. The assembly in accordance with claim 3 wherein said plungeris disposed at an open end of said inner housing and said plunger ismoveable by the gas to drive said plunger from an open end of said innerhousing and thereafter through said outer housing and into the impactwith the plunger receiver.
 7. The assembly in accordance with claim 1wherein said coupling device comprises a nut adapted for interlockingengagement with the open end of said outer housing and the selectedplunger receiver, and having a central bore extending therethrough. 8.The assembly in accordance with claim 7 and further comprising aremovable plug disposed on said nut for closing the central boretherethrough.
 9. The assembly in accordance with claim 1 wherein theelectric match is provided with electrical leads extending therefrom forconnection to an electrical power source.
 10. The assembly in accordancewith claim 9 wherein the electrical leads extend through said outertubular housing and extend outwardly from a second end of said outertubular housing.
 11. A firing pin assembly comprising: an outerelongated housing having an open end; an electric match, comprising anelectrical initiator and an explosive material, disposed in saidhousing; a firing pin disposed in said housing and moveable in saidhousing; and a coupling device for connecting said outer housing openend to an explosive primer assembly; wherein application of anelectrical charge to said electric match initiator activates saidelectric match explosive material to produce gas in said outer housingwhich drives said firing pin through said outer housing and into impactwith the explosive primer assembly.
 12. The assembly in accordance withclaim 11 and further comprising structure disposed in said outer housingfor retaining said electric match.
 13. The assembly in accordance withclaim 12 wherein said retaining structure comprises an inner housing.14. The assembly in accordance with claim 13 and further comprisingmeans for retaining said inner housing in said outer housing.
 15. Theassembly in accordance with claim 14 wherein said housings are tubularmembers and said outer housing is crimped into engagement with saidinner housing to effect the retaining of said inner housing.
 16. Theassembly in accordance with claim 14 wherein said firing pin is disposedat an open end of said inner housing and said firing pin is moveable bythe gas to drive said firing pin from the open end of said inner housingand thereafter through said outer housing and into the impact with theprimer assembly.
 17. The assembly in accordance with claim 11 whereinsaid coupling device comprises a nut adapted for interlocking engagementwith the open end of said outer housing and with the primer assembly.18. The assembly in accordance with claim 11 wherein the electric matchis provided with electrical leads extending therefrom for connection toan electrical power source.
 19. The assembly in accordance with claim 18wherein the electrical leads extend through said outer tubular housingand extend outwardly from a second end of said outer tubular housing.